Flotation cells have been used in mineral processing applications for over a hundred years. Mechanical cells (flotation cells that rely on an impeller to create agitation within the cell) have traditionally been the most common type of flotation cell. However, in more recent times, pneumatic flotation cells have become increasingly popular. One such type of pneumatic flotation cell is the Jameson cell, which has gained acceptance in a wide variety of applications, including base metals flotation, coal flotation, solvent extraction and waste water treatment.
The Jameson cell is a high-throughput flotation cell that significantly reduces the time required for conditioning of the feed material entering the cell. In traditional mechanical cells, a long conditioning time is needed to achieve the necessary contact between gas bubbles and reagentised particles in the feed stream in order that valuable mineral particles may be collected as a concentrate. By contrast, the Jameson cell uses a “downcomer” which acts as a plunging jet reactor to create a turbulent, high shear environment that provides excellent contact between bubbles and particles, significantly reducing the required conditioning time. Thus, the Jameson cell provides a number of benefits over mechanical cells, including higher throughputs, lower operating costs, less maintenance due to the presence of fewer moving parts and improved metallurgical performance. The Jameson cell is the subject of U.S. Pat. No. 4,938,865, and the disclosure of this document is hereby incorporated by reference.
The rise in popularity of the Jameson cell is due in large part to the improvements in flotation performance that can be obtained using this type of cell, coupled with a marked decrease in operating costs. In addition, due to the highly turbulent conditions created in the downcomer, there is much more efficient contact between gas bubbles, ore particles and reagents achieved in the Jameson cell than in conventional mechanical cells.
It has been found that recycling all, or part of, a flotation cell tailings stream to the feed inlet of the flotation cell may provide improved stability in the environment within the cell. In the past, however, the recycling of the tailings stream has been non-selective, which may result in small amounts of non-floating gangue material being recycled back into the cell, while, at the same time, it is possible that small amounts of the slow-floating valuable mineral will report to the tailings stream. Thus, there is considerable scope for the improvement of this process.
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